Expansion shell assembly

ABSTRACT

Mine roof expansion shell assembly having a one piece shell with annular ring and four expansion fingers with external gripping teeth extending from the ring, and an internal flat wedge engaging surface adjacent the other end, an expanding wedge having a threaded aperture for a mine roof bolt and wedge faces for each of the fingers, the fingers being spaced apart on opposite sides of the shell to form a slot for a wedge retaining U-shaped strap extending over the large diameter end of the wedge with its ends extending through the ring in grooves aligned with the slots, the ends being bent outwardly to engage the underside of the ring, the bent ends being held in place by resiliency of the strap, or the presence of a mine roof bolt threaded into the wedge, and extending through the ring.

ilriited States atent Discimw et a1.

[451 Apr. 10, 1973 [54] EXPANSION SHELL ASSEMBLY [76] inventors:Frederick P. Dickow, R.D. No. 6, Auburn, N.Y.; Clifford H. Lambert, 1 12Bridge St., Naugatuck, Conn.

[22] Filed: Mar. 24, 1971 21 Appl. No.: 127,701

52 us. ca ..ss/7s [51] Int. Cl ..Fl6b 13/10 [58] Field of Search..85/75, 76, 85, 86, 85/79, 74, 67, 73, 88, 82-84 [56] References CitedUNITED STATES PATENTS 2,647,431 8/1953 Lewis ..85/75 3,315,557 4/1967Dickow v.85/75 1,434,394 11/1922 Matthes... ..85/7S 2,373,585 4/1945Mancini ..85/75 2,783,673 Lewis 'et a1. ..85/75 FOREIGN PATENTS ORAPPLICATIONS 434,885 10/1967 Switzerland ..85/75 Primary ExaminerRamonS. Britts Att0rneyF. P. Keiper 5 7 ABSTRACT Mine roof expansion shellassembly having a one piece shell with annular ring and four expansionfingers with external gripping teeth extending from the ring, and aninternal flat wedge engaging surface adjacent the other end, anexpanding wedge having a threaded aperture for a mine roof bolt andwedge faces for each of the fingers, the fingers being spaced apart onopposite sides of the shell to form a slot for a wedge retainingU-shaped strap extending over the large diameter end of the wedge withits ends extending through the ring in grooves aligned with the slots,the ends being bent outwardly to engage the underside of the ring, thebent ends being held in place by resiliency of the strap, or thepresence of a mine roof bolt threaded into the wedge, and extendingthrough the ring.

4 Claims, 14 Drawing Figures PATENTEB 1 01975 3.726.181

sum 1 BF 2 INVENTORS FREDERICK P. DICHOW.

CLIFFORD WLAMBERT'. v

AT TORNEY PATENTEUAPR 1 @1975 3 ,1 1

INVENTORJ. FREDERICK P. DICKOW' CLIFFORD H. LAMBERT ATTORNEV EXPANSIONSHELL ASSEMBLY This invention relates to mine roof support bolts andmore particularly to the expansion shell and wedge assembly usedtherewith.

In mine roof expansion shell assemblies comprising a one piece shellhaving an annulus or ring from which a plurality of fingers, such asfour, extend, which are expanded by a threaded tapered plug or wedgedrawn into the shell, the plug and shell have heretofore been held inassembled relation, by being assembled over the extended threaded end ofa mine roof bolt, after applying to the bolt a thin nut having shearablethreads, the assembly being held on the extended threaded end of thebolt between the threaded wedge and frangible nut. In Dickow U.S. Pat.No. 3,315,557, an attempt was made to secure the assembly by using astrap having its ends hooked into windows inthe tip ends of two oppositefingers, the strap being of U shape and bridging over the wedge to holdit in position in the shell as an assembly without the presence of themine roof bolt, or the extended threaded end, as in the case of the thinshearable nut. These prior devices have draw backs,

either in competitive manufacture, or in actual use in the field. Toavoid separation of the wedge from the shell, the first requires thepresence of the bolt end, with a thread longer than would otherwise benecessary, while the second necessitates a casting having apertures inthe finger tips which may present difficulties, where castings ofmalleable iron are employed, and further requires the strap to be'hookedinto the aperture in such a way as to minimize interference with the useof the assemblies in the field and the wedging action.

The present invention is directed to an assembly wherein the parts arereadily assembled without the necessity of upsetting metal, ordistorting the shell and which can be assembled or disassembled in thefield, or furnished as assemblies without the bolt, with assurance thatthe wedge will remain in place in the shell end in the desired assembledrelation. More particularly the assembly comprises a wedge holding strapthat comprises arms that extend downwardly out of the way betweenadjacent opposite pairs of expansion shell fingers. The arms extendingthrough the ring, and by lateral projections hooks inplace below thering. The assembly resists separation of the parts, and when a mine roofbolt is threaded into position in the wedge, the strap ends arephysically held spread apart by the body diameter of the bolt, so thatno dislocation of the parts can occur except upon the actual expansionof a shell assembly within a bore after which the strap ends may yieldif necessary, and if forced to do so by further expansion.

The above and other novel features of the invention will appear morefully hereinafter from the following detailed description when taken inconjunction with the accompanying drawings. It is expressly understoodthat the drawings are employed for purposes of illustration only and arenot designed as a definition of the limits of the invention, referencebeing had for this purpose to the appended claims.

In the drawings, wherein like reference characters indicate like parts:

FIG. 1 is a front elevation of wedge assembly;

FIG. 2 is a side elevation of the assembly of FIG. 1;

an expansion shell and FIG. 3 is a side elevation taken at an angle of45 degrees from the assembly of FIG. 1;

FIG. 4 is a top plane view of an assembly;

FIG. Sis a view from below;

FIG. 6 is a sectional view taken on the line 6--6 of FIG. 1;

FIG. 7 is a view of an assembly in partially expanded relation againstthe rock wall of a mine roof bore;

FIG. 8 is a longitudinal sectional view of a shell;

FIG. 9 is an upper end view ofa shell;

FIG. 10 is a lower end view of the shell;

FIG. 11 is an upper end view of a wedge;

FIG. 12 is a side elevation of the wedge;

FIG. 13 is a bottom end view of the wedge; and

FIG. 14 is a sectional view taken on the line 1414 of FIG. 1 1.

In the drawings, there is shown an expansion shell 20, and wedge 22maintained in assembled relation by a U strap 24 extending over thewedge, with its ends 26 and 28 hooked below the lower end of the shell.The expansion shell, which may be made of a malleable iron casting,comprises four like expansion shell fingers 30, 32, 34 and 36 whichproject from a ring 38. Each finger comprises an outwardly facing flatsection 40 and a plurality of external arcuate gripping teeth 42 of sawtooth configuration.

Internally, each finger has a concave arcuate cylindrical surface 44formed as a projection of the internal diameter of ring 38, whichsurface 44 terminates in a flat inclined wedge engaging surface 46 ofeach finger, which wedge face may have an angle of about 8 from the axisof the shell. Between adjacent fingers are opposite slots 48 and 49, and50 and 51, having substantially parallel faces 52 and 54, adjacent thering end 38, which slots widen in the upper region so that the fingerstaper slightly in width. The upper end of each finger has an internalbevel 56 of about 45.

The slots 50 and 51 may be a little wider than the slots 48 and 49adjacent the ring to provide adequate space for the width of the strap24. The ring is provided on its inner surface with rectangular sectionedgrooves 58 and 59 aligned with the slots 50 and 51, such grooves beingof a depth corresponding to the thickness of the strap. The internaldiameter of the ring 38 is sufficient to loosely and freely clear thethreads 60, or the diameter of the support rod 62, which ever isgreater, the thread diameter being greater where rolled threads areprovided.

The wedge 22 comprises an internal threaded section and an enlarged endopening 72. Externally, it is provided with four wedge faces 74 planarin form and extending at an angle of about 8 from the wedge axis. On twoopposite sides between adjacent wedge faces 74, are inclined flat faces76, and 77 inclined at about.

4 or less, and on the remaining two opposite sides between wedge faces,the wedge has slightly conical surfaces 78.

I With the wedge in position in the end of the shell, 'without expandingthe shell, the strap 24 extends over the end of the wedge, with the Vbend 80 extending into the end opening 72. The side arms 82 and 84extend along and in contact with the side faces 76 and 77 of the wedge,and in the slots 50 and 51 between the adjacent fingers of the shell.The ends of the arms 82 and 84 lie in the grooves 58 and 59. The lowerends of the strap each have a right angle outward bend forming hook ends26 and 28.

It will be readily seen from the foregoing that assembly is effected byplacing the strap over wedge side faces 76 and 77, and extending thestrap ends downwardly through the ring aperture by sprining the endstogether slightly. When in position the strap ends spread into thegrooves 58 and S9, and the ends 26 and 28 embrace the lower end of theannulus or ring 38. In effecting assembly, no swaging, deforming orother operation requiring machine operations or brazing or welding isemployed, the three parts being readily assembled by hand without tools,if desired.

When an assembly is placed on the threaded end of a mine roof bolt, andis projected into a bore for expansion in hard rock stratta, suchinitial expansion of the shell fingers prior to insertion can beeffected to provide a suitable friction grip of the shell fingers on thebore wall. Thereafter, threading of the bolt into the wedge, with thebolt head bearing on a mine roof support plate, will draw the wedgedownwardly and expand the shell into holding relation with the bore. TheV bend in the strap may yield as shown in FIG. 7, and if necessary thelateral hook ends 26 and 28, may gradually yield and allow the strap toslip upwardly, as may be necessary, the yield being gradual and notrequiring any breaking away of the strap from the shell, or possibleinjury to the shell. It will also be seen that the strap located betweenfingers, can not interfere with the smooth action between the wedgesurfaces. The bolt end may be cupped as at 182 to swivelly receive andcenter the V bend 80.

While a single form of the invention has been illustrated and described,it is to be understood that the invention is not limited thereto. Asvarious changes in the construction and arrangement may be made withoutdeparting from the spirit ofthe invention, as will be apparent to thoseskilled in the art, reference will be had to the appended claims for adefinition of the limits of the invention.

What is claimed is:

1. A mine roof expansion shell assembly comprising, in combination:

a. a one-piece ring having concentric interior and exterior surfaces offirst and second diameters, respectively, and a planar lower surface;

b. four expansion fingers formed integrally with said ring and extendingsubstantially axially thereof from the surface opposite said lowersurface in spaced relation to one another, defining therebetween fourspaces of predetermined width at intervals, each of said fingers beingof substantially the same length and having a free end opposite thejuncture with said ring;

. a wedge disposed at least partly within the space enclosed by the freeends of said fingers and having a central, threaded aperture coaxialwith said ring, and four wedge faces, each in contact with a respectiveinternal surface of one of said fingers and sloped with respect to theaxis of said aperture and ring so that movement of said wedge towardsaid ring forces said fingers outwardly; and

. a substantially U-shaped strap extending over the end of said wedgefarthest from said ring, and through two opposite ones of said fourspaces, the width of said strap being less than said predeterminedwidth, and passing through said ring to terrninal end portions which arebent over to extend in closely ad acent, overlying relation to saidlower surface and terminate at ends spaced by a distance not greaterthan said second diameter and biased toward outward movement;

. the space between the opposing portions of said strap extendingthrough said ring being at least as great as the major diameter of saidthreaded aperture, and the length of said strap from said end portionsto the end extending over said wedge being less than the combined lengthof said fingers and said wedge, whereby said strap serves to retain saidwedge within the space enclosed by the free ends of said fingers.

2. The invention according to claim 1 wherein said ring includes a pairof slots spaced by on the internal periphery thereof to receive said endportions of said strap.

3. The invention according to claim 1 wherein said wedge includes a pairof strap clearance faces on opposite sides thereof adjacent which saidstrap extends, said strap clearance faces being disposed betweenadjacent ones of said wedge faces, and sloped at a lesser angle withrespect to said aperture and ring axis than said wedge faces.

4. The invention according to claim 3 wherein the angle at which saidstrap clearance faces are disposed withrespect to said axis isapproximately one-half the angle at which-said wedge faces are disposedwith respect to said axis.

1. A mine roof expansion shell assembly comprising, in combination: a. aone-piece ring having concentric interior and exterior surfaces of firstand second diameters, respectively, and a planar lower surface; b. fourexpansion fingers formed integrally with said ring and extendingsubstantially axially thereof from the surface opposite said lowersurface in spaced relation to one another, defining therebetween fourspaces of predetermined width at 90* intervals, each of said fingersbeing of substantially the same length and having a free end oppositethe juncture with said ring; c. a wedge disposed at least partly withinthe space enclosed by the free ends of said fingers and having acentral, threaded aperture coaxial with said ring, and four wedge faces,each in contact with a respective internal surface of one of saidfingers and sloped with respect to the axis of said aperture and ring sothat movement of said wedge toward said ring forces said fingersoutwardly; and d. a substantially U-shaped strap extending over the endof said wedge farthest from said ring, and through two opposite ones ofsaid four spaces, the width of said strap being less than saidpredetermined width, and passing through said ring to terminal endportions which are bent over to extend in closely adjacent, overlyingrelation to said lower surface and terminate at ends spaced by adistance not greater than said second diameter and biased toward outwardmovement; e. the space between the opposing portions of said strapextending through said ring being at least as great as the majordiameter of said threaded aperture, and the length of said strap fromsaid end portions to the end extending over said wedge being less thanthe combined length of said fingers and said wedge, whereby said strapserves to retain said wedge within the space enclosed by the free endsof said fingers.
 2. The invention according to claim 1 wherein said ringincludes a pair of slots spaced by 180* on the internal peripherythereof to receive said end portions of said strap.
 3. The inventionaccording to claim 1 wherein said wedge includes a pair of strapclearance faces on opposite sides thereof adjacent which said strapextends, said strap clearance faces being disposed between adjacent onesof said wedge faces, and sloped at a lesser angle with respect to saidaperture and ring axis than said wedge faces.
 4. The invention accordingto claim 3 wherein the angle at which said strap clearance faces aredisposed with respect to said axis is approximately one-half the angleat which said wedge faces are disposed with respect to said axis.